how to re-install evince in lucid

[mr.xulu]

Hi! I uninstalled evince pdf viewer wanting to try other pdf viewers. Now, I can't seem to install any pdf viewer and I can't re-install evince.

Whenever I try to install evince using ubuntu software center i get a window blocking the installation which says, "Required installation of untrusted packages: The action would require the installation of packages from not authenticated sources". I click "ok" and after a few seconds the installation process stops.

Please help. I have no pdf viewer.

Thanks a lot!

[webofunni]

Try

ALT+F2 --> gnome-terminal

sudo apt-get install evince

[mr.xulu]

Thanks a lot webofunni!